This section provides background information related to the present disclosure which is not necessarily prior art.
A vehicle typically includes a fuel tank that stores liquid fuel such as gasoline, diesel, methanol or other fuels. A portion of the liquid fuel in the fuel tank may evaporate into fuel vapor. An evaporative emissions control (EVAP) system is designed to store and dispose of fuel vapor to prevent and control unintended release into the atmosphere. For example, the EVAP system may return the fuel vapor from the fuel tank to the engine for combustion therein. Advanced plug-in hybrid vehicles may experience extended periods of time where engine operation is not required and turnover in the fuel tank is low. As a result, alternate venting arrangements may be used where the fuel tank is vented to atmosphere to control pressures within the fuel tank. Exposing the interior of the fuel tank to oxygen from ambient air may result in oxidation of the liquid fuel within the tank. Directly venting the fuel tank to the atmosphere may produce undesirable emissions as well as additional evaporation of liquid fuel within the fuel tank.